DAX behavior when Burstable instances go out of credits


Hello, I'd like to know what happens when cpu credits are out of balance for DAX? Will DAX bypass requests? Mostly I'd like to ensure that without cpu credits in DAX there won't be any soft of downtimes and situation wouldn't become worse comparing to normal dynamodb usage

asked 9 months ago179 views
2 Answers

If DAX is out of credit, it will return exceptions, it will not pass the request to DynamoDB for you. If you like, you can handle those exceptions and write/read around DAX, but then your cache becomes out of sync.

Its not recommended to use burstable instances for DAX for anything other than testing.

profile pictureAWS
answered 9 months ago
  • Thank you! In terms of normal instances , what would be the impact if I choose minimal ec2 instance type e.g. dax.r5.large but in fact more powerful instance type will be required?

  • Having an instance smaller than you need would most likely result in a low cache/hit ratio as you'd evict data due to it not being able to fit in memory. It could also cause throttling on connections if you create a lot of those also.


Thank you, @Leeroy Hannigan. Are there specific best practices for selecting the appropriate DAX cluster instances? Additionally, what preventive measures can we adopt to fully harness the potential of DAX?

answered 9 months ago

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